Albert Reynolds always maintained in private conversations that without Martin McGuinness there would have been no IRA ceasefire during his tenure as Taoiseach and what was known as 'the peace process' would have been seriously delayed or derailed as a result.

Albert Reynolds always maintained in private conversations that without Martin McGuinness there would have been no IRA ceasefire during his tenure as Taoiseach and what was known as 'the peace process' would have been seriously delayed or derailed as a result.

Because of his paramilitary activities and his long-time membership of the IRA Army Council, McGuinness had the "credentials" to talk on equal terms with the extremist 'physical force' Republicans and persuade most of them that the 'war' could never be won.

The freshest memories of McGuinness come from the more recent images of himself and Ian Paisley, dubbed 'The Chuckle Brothers'. Behind that fatherly facade was a hardened gunman; the "blue-eyed" boy from Derry with radical chic, lionised as the acceptable face of terrorism.

But, while he survived arguably one of the bloodiest conflicts in Europe in modern times, he spent much of his time carrying the coffins of those he had influenced to live and die by the gun. Observers marvelled that while close associates died in a hail of gunfire, he survived and thrived. James Martin Pacelli McGuinness was born on May 23, 1950, the second-born son to William and Peggy McGuinness, of Elwood Street in the Bogside of Derry. His father was employed for much of his life in Browns Iron Foundry. His mother Peggy was from Illies near Buncrana in Co Donegal.

His father and mother were devoutly Catholic and Nationalist/Labour in political outlook. In the years that followed his birth they would have a succession of children, Paul, Mary, William, Declan and Johnny, in addition to their eldest, Tom, who became a star Gaelic football player with Derry.

After failing his Eleven-plus State exam he was sent to Brow of the Hill Christian Brothers School, but left at the age of 15 and worked for James Doherty, a local butcher, packing bacon. He would later say that he had "a happy and largely uneventful" childhood. An ardent Manchester United fan, he steered clear of the early civil rights marches in Derry, but was well known around the city as something of a 'Teddy Boy' who neither smoked nor drank, but fancied himself with the girls. When what became known as 'The Battle of the Bogside' raged from August 12-14, 1969, McGuinness joined the rioters. "I threw stones, petrol bombs, anything else I could get my hands on," he said later. Known as one the 'Derry Young Hooligans', he was arrested and found guilty of disorderly behaviour.

He is believed to have joined the Official IRA some time in 1970, unaware of the December, 1969 split and the creation of the Provisional IRA. "There was a real exciting aspect to being on the run," he would later say, moving to different 'safe houses' and avoiding capture with the reintroduction of internment.

McGuinness soon defected to the Provisionals, quickly moving up the ranks, and, by the end of 1971, was believed to have become second in command of the Derry brigade.

The Saville Inquiry concluded that although McGuinness was probably armed with a Thompson sub-machine gun on Bloody Sunday, January 30, 1972, there was insufficient evidence to suggest that it had been used. The inquiry was satisfied "that he did not engage in any activity that provided any of the soldiers with any justification for opening fire".

Despite being "one of the most wanted men" in Northern Ireland, McGuinness seemed to have a Michael Collins complex, in that he relished being at the centre of attention. In the aftermath of Bloody Sunday he mingled in the City Hotel with hordes of newspaper and television reporters and was described in one profile, under the heading 'The Boy Who Rules Free Derry' as "fair-haired, handsome, with piercing blue eyes and an almost school-boy shyness about him".

With the declaration of an IRA ceasefire on June 26, 1972, McGuinness was part of the IRA delegation flown to London by the RAF for a secret meeting with Northern Secretary Willie Whitelaw. The talks came to nothing, but McGuinness met with M16 officer Frank Steele and would keep lines of communications open with him and another secret-service figure, Michael Oatley, in a delicate balancing act to keep informed of thinking at the highest level in the British government.

Knowing the value of propaganda, McGuinness brought celebrities like the actors Siobhan McKenna and Jane Fonda and writers Edna O'Brien and Leon Uris on conducted tours of 'Free Derry' as if he was really the alternative leader of the city.

His mentor in the Republican movement, it is said, was John Joe McGirl, a former Chief of Staff of the IRA and abstentionist Sinn Fein TD for Leitrim.

In December 1972, McGuinness was jailed in The Curragh after being caught with a 250lb bomb, and later in Portlaoise Prison for belonging to the IRA. Shortly after his release, on November 20, 1974 he married his long-time girlfriend Bernie Canning at Cockhill, Co Donegal, in the same church where his father had been buried the previous year.

In his role as an IRA commander he was also involved in the dangerous feuds with splinter organisations. He was particularly disappointed with the defection of Dominic McGlinchey to the ruthless Irish National Liberation Army (INLA) but after his friend was shot dead in Dundalk, Co Louth, he carried the coffin at his funeral.

In 1978, after the arrest of Gerry Adams, McGuinness was promoted from Director of Operations to Chief of Staff of the IRA. It was a role that involved him in the callous murder of Lord Louis Mountbatten near Classiebawn Castle in Co Sligo, and the killing of 18 British soldiers at an ambush in Warrenpoint, Co Down, on the same day, August 27, 1979.

According to Liam Clarke and Kathryn Johnston in their book, Martin McGuinness: From Guns to Government, years of 'active service' with the IRA had also taken their toll and he suffered from bouts of depression after the hunger strikes of 1981. Following a series of election victories north and south, McGuinness realised the value for Sinn Fein of pursuing the ballot box strategy.

He was elected to the Northern Ireland Assembly in Stormont in November, 1982 allegedly helped by massive Republican voter fraud, or personation. The rejection of 'Four Provinces Federal Solution' advocated by Ruairi O Bradaigh, President of Sinn Fein since 1970, also paved the way for the 'Northern takeover' by Adams and McGuinness in November, 1983.

According to intelligence sources, he and Adams rejoined the IRA Army Council the same year, but defections, exhaustion and improved cooperation between security services north and south of the border had the IRA close to defeat, and, in desperation, McGuinness sanctioned a series of high-profile assassination attempts on leading British figures, culminating in the Brighton bombing of 1984 and the attempted assassination of Prime Minister Margaret Thatcher. He was also pushing strongly through the mid-to-late 1980s for active IRA guerrilla operations. "I sat in a house in Donegal along with Martin McGuinness and the rest of the GHQ staff where they were planning... this major upsurge in the campaign," IRA commander Brendan Hughes told Ed Moloney on the Boston College Tapes. "Gaddafi had come on board... all the weapons were there. What was lacking was training but there was this sort of bullish attitude from people like McGuinness to push ahead with these operations." In his book Voices from the Grave Moloney quotes Hughes as saying: "But people wanted to go ahead with it and one person in particular... Martin McGuinness."

The 'Tet Offensive' as it was nicknamed in honour of the Viet Cong, quickly exposed the IRA as demoralised and riddled with informers. It was a point McGuinness didn't need reminding of as he carried the coffins of eight IRA members wiped out by the SAS at Loughgall, Co Tyrone in May, 1987 and the three members of the IRA unit shot dead by the SAS on a reconnaissance mission in Gibraltar in March, 1988.

After the protracted 'Hume Adams Talks' with SDLP leader John Hume, a high-level source within the IRA, who many believed to be McGuinness (but which he denied) sent a message to the British Prime Minister John Major, saying: ''The conflict is over, we need your advice on how to bring it to a close." According to Gerry Adams, there were attempts from within the 'movement' "to undermine Martin McGuinness and to discredit him in the eyes of other Republicans".

The then Taoiseach Albert Reynolds responded in October by sending his Northern Ireland advisor Martin Mansergh to the Redemptorist Monastery in Dundalk, Co Louth to talk with McGuinness. The breakthrough came with the tentative IRA ceasefire declared on September 1, 1994.

When it broke down 17 months later, after protracted discussions on decommissioning weapons, the IRA cynically detonated a massive bomb in the city of London within 24 hours, killing two innocent civilians, injuring 40 more. It was resumed on July 20, 1997.

"Re-instituting the ceasefire did not pose anything like the problems associated with the first one," said one of its architects, Martin Mansergh, recently, "we were really just picking up the threads [of 1994]".

A member of a delegation led by then Taoiseach Bertie Ahern recalled their excitement at being invited to Chequers, the country residence of the British Prime Minister, to meet Tony Blair urgently on a Sunday in the middle of one of the many crises along the way. They were gobsmacked to find McGuinness sitting in the kitchen as if he was completely at home in such surroundings. The then British Northern Ireland Secretary Mo Mowlam referred to him as 'babe'.

By then he had been elected to the Northern Ireland Forum for Foyle in 1996 and as MP for mid-Ulster in 1997. He was Sinn Fein's chief negotiator in the lead up to the Good Friday Agreement signed on April 10, 1998.

"In many ways Martin McGuinness is an exemplary man," said Bishop Edward Daly of Derry in 1999. "If you were in his bad books, he would treat you in a very tough, usually unpleasant way," said Northern Ireland Secretary Peter Mandelson who detested McGuinness's habit of poking him in the chest at moments of tension.

After the Agreement he was returned to the Northern Ireland Assembly and appointed Minister for Education. Following the St Andrews Agreement he was nominated, in May 2007, as Deputy First Minister in the Assembly under the leadership of First Minister Ian Paisley of the Democratic Unionist Party - a virulent critic of Sinn Fein, the IRA and McGuinness in particular.

After many years living in a council house in Derry, the McGuinness family, Grainne and Fionnuala and Fiachra and Emmet, moved to a new house built by McGuinness's brother Tom. He also had a holiday home in Donegal. For leisure, he liked television, books and had a passion for salmon and trout fishing.

When he contested the 2011 Irish Presidential election he found the electorate in the Republic less sympathetic to his ideology, although he came third, with 243,000 votes.

He resigned as MP for mid-Ulster in 2012 and when Sinn Fein changed its position on the 'Cash for Ash' scandal, McGuinness resigned as Deputy First Minister of the Assembly on January 9, 2017. On January 19, looking gaunt and ill, he announced that he would not be standing for re-election and was retiring from politics.

Reportedly suffering from amyloidosis, a condition that attacks the vital organs, particularly the heart, he is believed to have undergone a course of chemotherapy and been hospitalised earlier this month. His death last Tuesday morning at the age of 66, brings to an end one of the most remarkable paramilitary/political careers in modern Irish history.